Step 1: Bake the Chocolate Cake

1. Preheat oven to 350°F (175°C). Grease and line a 9-inch round cake pan with parchment paper.
2. In a large bowl, whisk together flour, cocoa powder, sugar, baking powder, baking soda, and salt.
3. Add buttermilk, vegetable oil, eggs, and vanilla extract. Mix until just combined.
4. Slowly pour in hot water or coffee, stirring until smooth. The batter will be thin—this is normal!
5. Pour into the prepared cake pan and bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.
6. Let cool for 10 minutes in the pan, then transfer to a wire rack to cool completely.

Step 2: Make the Chocolate Ganache

1. Heat the heavy cream in a small saucepan over medium heat until it just starts to simmer (do not boil).
2. Pour the hot cream over the chopped dark chocolate in a heatproof bowl. Let sit for 2-3 minutes.
3. Stir gently until the chocolate is fully melted and smooth.
4. Add butter and mix until the ganache is glossy. Let cool slightly before using.

Step 3: Create the Chocolate Nest

1. Line a small bowl or a plate with parchment paper.
2. Transfer melted dark chocolate to a piping bag (or use a spoon) and drizzle it in a crisscross pattern to form a nest shape.
3. Chill in the refrigerator for 15-20 minutes, until firm.

Step 4: Assemble the Cake

1. Place the cooled chocolate cake on a serving plate.
2. Pour the chocolate ganache over the cake, letting it drip naturally over the edges.
3. Carefully place the chilled chocolate nest on top of the cake.
4. Fill the nest with mini chocolate eggs or candy-coated Easter eggs for a festive touch.

Step 5: Serve and Enjoy!

1. Let the cake sit for 10 minutes before slicing to allow the ganache to set slightly.
2. Serve at room temperature or slightly warmed for a gooey ganache experience.